Around £8m worth of Olympic and Paralympic stamps were sold during the London 2012 Games, helping to boost profits at the Post Office. The hugely popular stamps featured UK gold medallists. More than 500 branches opened on Sundays during the Games, many for the first time, so the stamps could be sold the day after a gold medal victory.

In its first trading statement since separating from the Royal Mail in April, the Post Office said operating profit in the first half of the financial year was £61m, up by £5m on the same period last year. Turnover rose £16m to £501m, with "continued strong performance" in the mail business, especially packets and special deliveries.

The Post Office said its network was at its most stable for more than 25 years, with 11,799 branches and a commitment to no further closure programmes. More than 250 branches have been converted into shops, with extended opening hours, while the partnership with the Bank of Ireland has recently been extended for a further three years.

Jo Swinson, the minister responsible for the Post Office, said: "I am pleased to see Post Office continuing to make progress as an independent business, and these results show that with the support of this government, Post Office's management has successfully been able to reverse two decades of decline."

"Post Office has achieved a considerable amount in these past six months and I firmly believe this provides the business, and its stakeholders, with a strong platform for continued growth and development in the future."

A Communication Workers Union spokesman said: "The Post Office results are good so we now want the company to reward staff for contributing to this success.

"Over 4,000 Crown Office staff have been waiting for a pay rise since April while other people in the organisation have had increases.

"Now that we all know the Post Office finances are positive we hope that management will reward the staff who have been so instrumental in making the Post Office a success."